Push rod and process



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PUSH ROD AND PROCESS Filed June 3. 1959 INVENTOR ATTORNE Patented Nov. 18, 1941 PUSH non AND PROCESS Adolph Werme, Worcester, Mass, assignor to Reed & Prince Manufacturing Company,

Worcester, Mass, a corporation of Massachusetts Application June 3, 1939, Serial No. 277,243

2 Claims.

The present invention relates to hollow push. V

rods and to processes for forming the same.

The invention has for its object the provision of improved push rods and processes. By the invention there is provided a push rod combining relatively light weight with strength and ease of manufacture.

As is well known, push rods are used in internal combustion engines for opening the valves in the combustion chambers. One end of the push rod is provided with a cam follower and the other end with a socket which receives a ball screw. The ball screw, in turn, is threaded into a pivoted tappet, the other end of the tappet being attached to the valve. When the push rod is raised in response to the contour of the cam, the tappet customarily depresses the valve stem and opens the valve.

Push rods have been made in the form of solid rods, but with modern high speed engines difficulty has been experienced with vibration of such rods. Improved results in this respect are obtained by the use of hollowpush rods.

In accordance with the present invention, the socket on the end of a hollow push rod, for receiving the ball screw, is formed by folding in upon itself the material at one end of the hollow rod or tube and compacting and forming the thus folded material into the shape of a socket.

For a better understanding of the invention, reference may be had to the accompanying drawing, in which,

Fig. l is an elevational view illustrating a hollow rod suitable for use in accordance with the invention;

Fig. 2 is an elevation, partly broken away, showing the socketend formed on the rod;

Fig. 3 is a partial section on the line 3-3 of Fig. 2, illustrating the formation of the socket end of the rod; and

Fig. 4 is an elevation, partly broken away, showing the push rod operatively connected to a tappet and also showing the cam follower on the opposite end of the rod.

In the practice of the invention, a hollow metal rod or tube of convenient form, as shown at H in Fig. 1, may be used. The folding in upon itself of the material at one end of this hollow rod, and. the compacting and shaping of the thus folded material into a socket, may conveniently be done in a heading machine provided with appropriately formed punches and sockets or dies. As will be seen by reference to Fig. 3 of the drawing, the finished socket l3 in the head I2 on the end of the hollow rod ll comprises a folded portion of the rod, a fold line being indicated by the reference numeral l4. In this folding operation and the operation of shaping the socket, the material is folded and flowed in toward the center of the rod so that it preferably substantially closes the hollow in the rod,

- as seen for example in Fig. 3. At the same time,

the folding of the material and the compacting and Working of the metal provide increased thickness and strength in the socket.

The finished rod in association with a tappet is illustrated in Fig. 4, where the ball screw I5 is seen in position in the socket and threaded into one end of the tappet IS.

The end of the push rod opposite the socket is provided with a cam follower. This may conveniently be done, as illustrated in Fig. 4, by enlarging the end of the rod II, as indicated at I1, and inserting a cam follower member I8 into this enlarged portion of the rod.

Although I prefer to fold the material in upon itself to provide a socket to receive a ball screw, I may direct the forming means against the material in such a manner as to mold the socket while minimizing the folding phenomenon referred to and illustrated in Fig. 3. In this case the socket portion would be substantially of a single thickness of material and would not possess various advantages which follow the folding above described.

} Various modifications in the exact form herein shown and described may be resorted to in keeping with the spirit of the invention as defined in the appended claims.

I claim:

In a method for making a push rod, the steps which comprise folding one end of a length of metal tubing, open at said end, inwardly upon itself, compacting said inwardly folded end against the inner wall of the tube, working and flowing the metal and extending the same inwardly over the hollow in the tubing, thus forming a socket portion integral with a tubular stem and substantially closing the opening in the tube, said method including the step of forming the socket portion with a diameter larger than the diameter of the stem portion.

2. A push rod comprising a hollow rod formed from an open'ended tube, and having integral therewith a socket portion which has a generally semi-spherical bottom extending to a substantial extent over the hollow in said rod, said socket comprising a portion of the rod adjacent the original open end, folded inwardly upon itself in contact with the interior surface of the hollow rod, but being of a single thickness of material where it extends over said hollow in the rod, said socket having a diameter greater than the diameter of the stem of the push rod.

ADOLPH WERME. 

